Live- cell imaging under centrifugation characterized the cellular force for nuclear centration in the Caenorhabditis elegans embryo

• 成果类型: Article
• 署名作者: Goda, Makoto; Shribak, Michael; Ikeda, Zenki; Okada, Naobumi; Tani, Tomomi; Goshima, Gohta; Oldenbourg, Rudolf; Kimura, Akatsuki
• 署名单位: Marine Biological Laboratory - Woods Hole; Hamamatsu University School of Medicine; Nagoya University; Research Organization of Information & Systems (ROIS); National Institute of Genetics (NIG) - Japan; Graduate University for Advanced Studies - Japan; National Institute of Advanced Industrial Science & Technology (AIST)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13657
• DOI: 10.1073/pnas.2402759121
• 发表日期: 2024-10-22
• 关键词: polarizing microscope; pulling force; zyg-9 form; spindle; centrosome; protein; mechanics; migration; geometry; complex

摘要

Organelles in cells are appropriately positioned, despite crowding in the cytoplasm. However, our understanding of the force required to move large organelles, such the nucleus, inside the cytoplasm is limited, in part owing to a lack of accurate methods for measurement. We devised a method to apply forces to the nucleus of living Caenorhabditis elegans embryos to measure the force generated inside the cell. We used centrifuge polarizing microscope to apply centrifugal force and orientation- independent differential interference contrast microscopy to characterize the mass density of the nucleus and cytoplasm. The cellular forces moving the nucleus toward the cell center increased linearly at-12 pN/mu m depending on the distance from the center. The frictional coefficient was-980 pN s/mu m. The measured values were smaller than the previously reported estimates for sea urchin embryos. The forces were consistent with the centrosome- organelle mutual pulling model for nuclear centration. The frictional coefficient was reduced when microtubules were shorter or detached from nuclei mutant embryos, demonstrating the contribution of astral microtubules. Finally, the frictional coefficient was higher than a theoretical estimate, indicating the contribution of uncharacterized properties of the cytoplasm.